An image sensor is typically classified as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) image sensor (CIS).
The CIS generally includes photodiodes and MOS transistors in unit pixels. The CIS sequentially detects electrical signals of respective unit pixels in a switching manner to realize an image.
A microlens is typically formed on a color filter to enhance the light sensitivity of the CIS. Generally, the microlens is formed in a domed shape by sequentially performing an exposure process, a development process, and a reflow process with respect to a photosensitive organic material.
However, since the photosensitive organic material has weak physical properties, the microlens may be damaged by physical impact after being formed such as during a packaging process or a bump process. Also, since the photosensitive organic material has relatively high viscosity, a defect may be generated in the microlens from particles adsorbing thereon.
Thus, there exists a need in the art for an improved image sensor and method for manufacturing the same.